A little work (3)
I believe the answer is:
erg
'a little work' is the definition.
(erg is a scientific unit for work)
This is the entire clue.
(Other definitions for erg that I've seen before include "Unit of work (phys.)" , "Amount of work" , "What's used to record work" , "Unit of work or energy" , "Shifting dunes in Sahara" .)